Reduction in Hybridization: Lone Pairs Interacting with Empty p Orbitals

<div> <div> <div> <p>X−NH2 and X−OH (for X = Li, BeH, BH2, Na, MgH, and AlH2) exhibit a reduction in hybridization in the N and O atoms, and likely in F, as well. CCSD(T)-F12/cc-pVTZ-F12 optimizations for all combinations of atoms smaller than chlorine (excluding the noble gasses) where the standard valences are filled with hydrogen atoms give breaks in the expected periodic trends. While most bond energies for a given atom increase when bonded to all atoms across a given row in the period table, X−NH2, X−OH, and X−F actually have the strongest bonds with X = BH2 and AlH2. Furthermore, the buildup in bond energy from the alkali to alkaline-earth metals is steady, and the decrease to Group 14 and beyond is also steady. The interactions of X−NH2 and X−OH with X = Li, BeH, BH2, Na, MgH, and AlH2 also produce either linear or fully planar geometries. All of these factors imply that the lone pair on the N or O atoms are datively bonding with the empty <i>p</i> orbitals in the other atoms. This leads to a reduction in hybridization. The non-periodic strengths of these bonds have implications for the detection of molecules in space as well as in models for the formation of refractory molecules and condensation of mineral species in early stages of planet formation. </p> </div> </div> </div>

Reduction in Hybridization: Lone Pairs Interacting with Empty p Orbitals

<div> <div> <div> <p>X−NH2 and X−OH (for X = Li, BeH, BH2, Na, MgH, and AlH2) exhibit a reduction in hybridization in the N and O atoms, and likely in F, as well. CCSD(T)-F12/cc-pVTZ-F12 optimizations for all combinations of atoms smaller than chlorine (excluding the noble gasses) where the standard valences are filled with hydrogen atoms give breaks in the expected periodic trends. While most bond energies for a given atom increase when bonded to all atoms across a given row in the period table, X−NH2, X−OH, and X−F actually have the strongest bonds with X = BH2 and AlH2. Furthermore, the buildup in bond energy from the alkali to alkaline-earth metals is steady, and the decrease to Group 14 and beyond is also steady. The interactions of X−NH2 and X−OH with X = Li, BeH, BH2, Na, MgH, and AlH2 also produce either linear or fully planar geometries. All of these factors imply that the lone pair on the N or O atoms are datively bonding with the empty <i>p</i> orbitals in the other atoms. This leads to a reduction in hybridization. The non-periodic strengths of these bonds have implications for the detection of molecules in space as well as in models for the formation of refractory molecules and condensation of mineral species in early stages of planet formation. </p> </div> </div> </div>

Влияние ультрадиспергирования на химические сдвиги рентгеновских K-линий в оксидах меди и марганца

The results of study of shifts of X-ray Kα and Kß lines of manganese and copper obtained for CuO, MnO, Mn3O4 and MnO2 oxide nanoparticles (relative to the corresponding massive materials) are presented. Oxide nanoparticles were synthesized in the pores of borosilicate glasses with an average pore diameter of 7±1 nm from the corresponding nitrates introduced into the pores by capillary impregnation. It was found, that for nanocomposites with CuO and Mn3O4 there is a small (about ~0.1 el./atom) increase in the role of 3d electrons in the chemical bonds. On the contrary, for nanocomposites with MnO2 the role of these electrons has an opposite trend.

Conclusive Research Design and Development of the Effect of Linear Deformation on Some Debye Properties of Metals

This Work, Debye Temperature And Debye Frequency Of Metals Were Computed And Studied Using Quantum Einstein Theory. The Electron Density Parameters Of Strained Metals Is Obtained And Used In The Computation.. The Results Obtained Revealed That There Is Agreement Between The Computed And Experimental Values Of Debye Temperature And Debye Frequency. This Shows That The Model Can Be Used To Study Debye Properties Of Metals. The Debye Temperature And Debye Frequency Obtained Are More Concentrated In The High Density Limit. This Revealed That Debye Temperature And Debye Frequency Of Metals Depend On The Electronic Concentration. Also, The Experimental Value Of Debye Temperature And Debye Frequency Is Higher Than The Computed Value, This Is Because Of Some Factor Which Debye Temperature And Debye Frequency Relied On That The Theory Failed To Account For. Debye Temperature And Debye Frequency Of Metals Reduces As Strain Increase. This Shows That As Strain Increase, Space Between Lattice Atom Increase Which Reduces Strength Of Electron Interaction And There-By Forces Debye Temperature, Debye Frequency To Decrease As Deformation Increase. This Behavior Of Metals Reveal That Debye Temperature And Debye Frequency Is Greatly Affected By Deformation.

THE ELECTRONIC STRUCTURE AND MAGNETISM OF CrSb WITH LATTICE CONSTANTS

The electronic structure and magnetism of CrSb compounds have been studied by a periodic quantum-mechanical calculation based on density functional theory. The results show that a ferrimagnetic ordered phase of CrSb in the Zinc-blende structure (ZB) is stable with half metallic properties, whereas the antiferromagnetic phase of CrSb in the NiAs -type crystal structure is energetically favored with no-gap band. The lattice constants have significant influence on the magnetism of CrSb . The band gap and the magnetic moment of Cr atom increase with increasing lattice constant in ZB CrSb . The effects on magnetic moment in the NiAs -type crystal structure are more sensitive substantially to the change of lattice constant a as compared with that of the lattice constant c. It is found that apart from ionic or metallic bonds there are covalent bonds between Cr d and Sb p orbitals in ZB CrSb , while bonding between Cr and Sb atoms is mainly ionic or metallic in CrSb of NiAs structure.

The interaction of dimethyl sulfoxide with N-benzoyl amino acids

The interaction of dimethyl sulfoxide with N-benzoyl amino acids in deuterochloroform has been investigated by 13C n.m.r. spectroscopy. Examination of the chemical shifts of the benzene ring reveals that intermolecular hydrogen bonding between dimethyl sulfoxide and the amido-hydrogen atom increase the effective steric size of the amino hydrogen, resulting in an increase in the torsional angle between the benzene ring and the C(O)NHCH(R)COOH side chain. Self-association of N- benzoyl amino acids in deuterochloroform occurs largely through two COOH...O=C hydrogen bonds and does not involve intermolecular hydrogen bonding to the N-H proton.